Until now, most of the talk about Zika has revolved around the risks for pregnant women: If you contract the virus while you’re preggers, you could infect your unborn child and raise the risk of potentially horrifying birth defects and developmental issues. But the risks of Zika for men aren’t discussed quite as much, mostly […]

Until now, most of the talk about Zika has revolved around the risks for pregnant women: If you contract the virus while you’re preggers, you could infect your unborn child and raise the risk of potentially horrifying birth defects and developmental issues.

But the risks of Zika for men aren’t discussed quite as much, mostly because people wrongly think that so long as a guy uses condoms after visiting a Zika-infected area, something that’s recommended for six months regardless of whether he develops Zika symptoms, no harm, no foul.

In fact, science has already linked Zika to neurological issues ranging from vision loss to temporary paralysis, while also increasing your risk of depression, Alzheimer’s disease, and other cognitive issues — so just getting Zika can pose risk for all adults, regardless of your gender.

On top of all those scary risks (Sorry, did you want to sleep tonight?), an alarming animal study recently published in the Nature suggests guys could have even more cause for concern: In the study, researchers injected the Zika virus into mice. Within three weeks, the virus not only traveled to their testicles, but destroyed the testicles’ internal structure and shrank the organs to one-tenth of their normal size. But the real fear here has nothing to do with aesthetics or vanity.

When the testicle structure is compromised, they can’t continue to produce sperm and testosterone, status quo. It’s why, six weeks into the experiment, the mice produced 10 times fewer sperm with noticeably lower levels of testosterone, all of which is to say the virus seriously messed with their fertility — and left them four times less likely to impregnate other mice compared to perfectly healthy mice. The mice didn’t heal even six weeks later, when the virus had left their systems.

While this experiment was done on mice, not people, it implies that Zika could be bad news for human males too. “While our study was in mice — and with the caveat that we don’t yet know whether Zika has the same effect in men — it does suggest that men might face low testosterone levels and low sperm counts after Zika infection, affecting their fertility,” said Michael Diamond, MD, PhD, a co-senior author on the study and the Herbert S. Gasser Professor of Medicine, in a press release on the study’s findings.

Of course more research is needed to figure out exactly how Zika could affect men’s fertility, and whether the symptoms are as dramatic and destructive in humans as they are in mice. Until all that’s sorted, any guy who thinks he’d maybe like to father a child one day should probably take caution when traveling to areas where Zika’s being transmitted. Because really, what trip is worth the risk?